1. Field of the Invention
The invention relates to a PCM recording system with a synchronizing signal like that of a television video signal.
2. Description of the Prior Art
In a conventional tape index counter to indicate a tape running position, a rotation of a tape reel 1 is transferred by a belt 2 to a mechanical counter 3 and then the mechanical counter 3 indicates the number of rotations of the tape reel 1, as shown in FIG. 1. The index counter accordingly does not indicate a real position of a running tape but does only the number of rotations of a take-up (or feeding) reel. Therefore, the index counter must be reset at the start of the tape winding, for example. A winding condition of the tape or a slip of the belt causes the counter to frequently indicate an erroneous indication, with the result that it is almost impossible to know a correct running tape position. Furthermore, the conventional index counter is insufficient for knowing the remaining time of the tape running. Additionally, even if the tape used has a fixed length, an indication by the index counter changes depending on the thickness of the tape, and the start or the end of the tape winding.
In order to automatically stop or rewind the running tape at a desired position, conventional measures taken for this are the use of an indication by the above-mentioned index counter, the use of a conductive sensing foil sticked onto the tape surface, and the like. The measure using the index counter, however, suffers from disadvantages as mentioned above such as poor accuracy of the tape position detection. The measure using the sensing foil is disadvantageous in that the sticking work of the sensing foil is troublesome, the sensing foil once sticked is hard in peeling it from the tape, and it is problematic when it is applied to the cassette type tape.
An additional disadvantage listed of the conventional PCM reproducing system is to require a separate test tape with a special random pattern record for adjusting a PCM signal distinguishing level, i.e. a slice level of 0 and 1.